Expansion-bit for coal-drills.



A l PUBMED MARR-,1906. w.H.cLARKsoN.

' EXPANSION BIT POR OOAL'DRILLS.

APPLIUATION FILED JAN. so, 1905.

UNITED sTATEs PATENT oEEroE.

WILLIAM H. CLARKSON. OF EDWARDS STATION, ILLINOIS, ASSIGNOR TO ELUIDEJ. CLARKSO'N, OF EDWARDS STATION, ILLINOIS.

Specification of Letters Patent.

Patented Mai-chA '13, 190e.

Application led January 3b, 1905. Serial No. 243,443.

To all whom it ma@4 concern:

Be it known that I,W1LLIAM H. CLARKSON,

This invention pertains to extensible or eX- pansion bit ends for coal-drills; but said invention is equall applicable to rock and other drilling of li e nature.

The object of the invention is to provide a bit'that can be. employed for boring holes of varying diameters.

In drilling coal it has been found to be of advantage to bore a hole of any desired size to start with and then some distance Within said bore to make a bore of greater diameter, thus forming a pocket in whichto place the charge of powder for blasting purposes. By this means a larger charge of powder can be used in a given spot, and the likelihood of blowing out the plugof the first or smaller bore is reduced. l A further object of the invention is that one drill is all that is necessaryto make borin s of different diameters without the need of avingseveral sized drills.

In the accompanying drawings, Figure 1 is view of my improved expansible bit in which two cutters are mounted on the end of a drill and shown separated. Fig. 2 is ay similar view lshowing the cutters or jaws closed nearly together. Fi 3 is an edge view of the device shown in lgs. 1 and 2. Fi 4 is a general view of a member for separatlng the cutters or permitting them tov approach one another. ig. 5 is a similar view of said member, but showing the same as it appears when given a quarter-turn from the osition shown in Fig. 4. 6 is a view o the bit similar 'to that showin in 3, but showing a modified form of the mem er for separating the jaws. -Fi 7 is an end section of the bit through line 'X, Fig. 2, showin the modilied form of separating member il ustrated in 6, IIA indicates Vthe drill usually em loyed in drilling operations and which 'is o a spiral form, as suggested in the gures, though not fully shown, but which will be readily understood by those skilled in the art to which the device relates.

At B B are two cutters or jaws of substantially the form shown in Fig. 3 and which are merely curvedA bodies of steel biurcated at their rear ends, the forward or cutting ends of the cutters being curved in opposite directions, as shown. The cutting edges are beveled, preferably, so that they may be ground when desired 4to give sharp points. As shown in the iirst two figures, the jaws or cutters are curved or extended at each side, so as to drill a hole of larger diameter than the drill-body A even when the said cutters are brought close together. free of the material to be drilled into, so that there will be no binding during the boring operation.

C C represent pivots by which the cutters are mounted upon the drill-body A for permitting the said cutters to have free movement'toward and away from each other, as will be understood. The ilattened end of the drill is provided with a hole, as at D, between the cutters. In this hole is inserted a member E, having a middle circular enlar ement F, which occupies a position within t e said hole D. Extending above and below tlus enlargement are two iiat portions G, ldesigned tolie between the bifurcated ends of the cutters. At one end of the member is a head H and at the other a nut J. In Fig. 1 the said member E lies so that the attened portions G (the upper one only being shown) lie parallel with the cutters, and this allows the extremities of the latter back of the pivots C to approach one another, the cutting ends 1n consequence being spread widely apart or to their llmit of extension. In Fig. 2 the meniber E is given a quarter-turn from the posl-v tion shown in Fig. 1, so that the said iiattened portions lie at rlght angles to the length of the cutters. Preferably, though not necessarily, a notch K is-cut in theadjacent edges of the cutters, as shown, into which the ed es of the portions G enter, as shown in said 1 2. By .this means the bit may be set to dr. l holes of two different diameters, and it will be observed that the head H and the nut J serve to iirmly' bind the cutters so that the will not rock or strain o n the drill A. It wi l be seen, further, that by the use of the said nut J the parts may be tightened and loos- This allows the said drill A to be- IOO ened when desired in order to make the changes above described.

In Figs. 6 and 7 a modified form of the adjusting means is illustrated. The cutters and the drill-body are the same as shown in the other figures; but in lieu of the member E described is employed amernber L, which has l a straight body to enter the hole D and having a tapered head M, .which lies between the ends of the cutters. Any adjustment of the latter devices may be had by a simple turn of the nut N. As the head is drawn down it spreads the rear ends of the cutters,land consequently draws the cutting edgesl thereof closer together, with the result that the hole boredthereby will be smaller than when the head 1s raised to permit the rear ends to approach each other for a larger hole. I may employ either form of adjustin means or even others that may be adapte lto accomplish thesame end.

The advantages of my improved form of drill are manifest, and it will be seen that it may be used for all drilling purposes where blasting is to be done.`

The advantage of the form of adjusting means shown in Figs. 6 and 7 is that any sized hole within the range 'of the drill may be bored, since the tapering head will spread the cutters in pro ortion to the adjustment of the nut N. en a borinfihas been made of the size produced by the device in its closed position, (shown in Fig. 2, the bit is withdrawn, the adjusting mem er moved to permit the cutters to be free, and the drill rentered. As the said cutters meet the work they naturally spread as the pressure comes u on themuntil they are open to their fullest width, and thus the enlarged hole is bored. At many times a boring of this kindis found to bedesirable, and I have provided a device that will accomplish it in any easy and. thorough manner. Another advantage is that if the operator wishes a hole of large size at some de th it is n ot necessary to make that hole of llarge diameter for .the entireboring, as that would make too much work; but a hole of small diameter can be more easily and uickly bored and then the larger one contmued at the depth desired.

, I claim- 1. Infa'coal-.drllL the-drill-body, cutting members bifurcated atone end and straddlin the said body, the same being pivoted to t e body, adjustable means back of the pivots of the members for closing such memers together at their cutting extremities, said adjustable means capable of being adjusted to'permit the members to separate at will when working Within a boring.

2. In a coal-drill, the drill-body, a pair of bifurcated members straddling the extremity of the body, and pivoted to the said extremity, said members having cutting edges at thelr free extremities, and means rearward of the pivots for separating the rear ends ofthe members to close the free ends together. f

3. In a coal-drill, the drill-body, a pair of cutting members bifurcated at one end and inclosing the extremity of such drill-body, each being pivoted thereto, the iree extremity of the members having cutting edges and* adapted for separation b swinging on the pivots, said cutting edges eing substantially at ri ht angles to the axis of the drill-body whet er separated o`r closed together and means for closing' the members together, such means also when adjusted permitting the members to se arate when a hole of larger diameter is to e bored.

4. In a coal-drill,`the drill-body, a pair of bifurcated members straddling the extremity of ,the said body and pivoted thereto and adapted to se arate or close together, a member carrie in the body rearward of the pivots of'the members, t e same adapted when in one position to close the free cutting ends of the members together vand in the other position to .permit the said cutting ends to separate at wil 5.. In a coal-drill, the drill-body, a pair of cuttin members bifurcated at one end to stradd e the extremity of the body and pivoted thereto, a member carried in the drillbody between the members rearward of the pivots, the same being adjustable to permit the free ends of the members to separate or to positivelyclose them together for the purposesy set forth.

roo

In testimony whereof I alix my signature in presence of two witnesses.

WILLIAM H. CLARKSON. Witnesses:

L. M. TnURLow, E. J. ABERsoL. 

